MMSZ5259B-TP Zener Diode 39V 500mW SOD-123 Equivalent & Substitute Parts

Part Overview

The MMSZ5259B-TP is a 39 V, 500 mW Zener diode manufactured by Micro Commercial Co in SOD-123 surface mount package. This component is classified as Active and is ROHS3 compliant. The part is supplied in Tape & Reel packaging with 896 units currently in stock.

Equivalent and substitute parts are necessary when the primary part becomes unavailable, when alternative packaging formats are required for manufacturing processes, or when sourcing from multiple qualified manufacturers is required for supply chain resilience.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	39	V
Tolerance	±5%	—
Power - Maximum	500	mW
Impedance (Maximum)	80	Ohms
Current - Reverse Leakage @ Vr	100 nA @ 30 V	—
Voltage - Forward (Maximum) @ If	900 mV @ 10 mA	—
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOD-123	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MMSZ5259B-TP is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage: 39 V nominal
Power rating: 500 mW maximum
Tolerance: ±5%
Package: SOD-123 surface mount
Operating temperature range: minimum -55°C to 150°C
Forward voltage: 900 mV maximum @ 10 mA
Reverse leakage current: 100 nA @ 30 V or lower

Secondary Considerations:

Impedance (Zzt): 80 Ohms nominal for MMSZ5259 series; 130 Ohms acceptable for alternative series
Packaging format: Tape & Reel (TR), Cut Tape (CT), or Digi-Reel acceptable
Manufacturer qualification: ROHS3 compliance required; AEC-Q101 qualification optional for automotive applications
Product status: Active preferred; Obsolete parts listed for reference only

Parts are grouped as Direct Manufacturer equivalents, Similar alternatives, or Parametric equivalents based on electrical parameter alignment and manufacturing source.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Ir @ Vr	Vf @ If	Temp Range (°C)	Package	Status
MMSZ5259B-TP	Micro Commercial Co	39	±5%	500	80	100 nA @ 30 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active
MMSZ39T1G	onsemi	39	±5%	500	130	50 nA @ 27.3 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active
SZMMSZ39T1G	onsemi	39	±5%	500	130	50 nA @ 27.3 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active
BZT52C39-13-F	Diodes Incorporated	39	±5%	500	130	100 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150	SOD-123	Active
BZT52C39-7-F	Diodes Incorporated	39	±5%	500	130	100 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150	SOD-123	Active
BZT52C39Q-7-F	Diodes Incorporated	39	±5.13%	370	130	100 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150	SOD-123	Active
DDZ9716-7	Diodes Incorporated	39	±5%	500	—	50 nA @ 29.6 V	900 mV @ 10 mA	-65 to 150	SOD-123	Active
MMSZ5259B-7-F	Diodes Incorporated	39	±5%	500	80	100 nA @ 30 V	900 mV @ 10 mA	-65 to 150	SOD-123	Active
MMSZ5259B-E3-08	Vishay General Semiconductor	39	±5%	500	80	100 nA @ 30 V	—	-55 to 150	SOD-123	Active
MMSZ5259B-HE3-08	Vishay General Semiconductor	39	±5%	500	80	100 nA @ 30 V	—	-55 to 150	SOD-123	Obsolete
MMSZ5259BT1G	onsemi	39	±5%	500	80	100 nA @ 30 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active

Engineering Selection Recommendations

Direct Electrical Equivalents (Identical Specifications):

The MMSZ5259BT1G (onsemi) and MMSZ5259B-7-F (Diodes Incorporated) are direct electrical equivalents to the MMSZ5259B-TP. Both maintain identical Zener voltage (39 V), power rating (500 mW), impedance (80 Ohms), and reverse leakage characteristics (100 nA @ 30 V). Both are ROHS3 compliant and Active status. The MMSZ5259B-7-F extends the operating temperature range to -65°C, providing additional margin for low-temperature applications.

Parametric Equivalents (Functionally Compatible):

The MMSZ5259B-E3-08 (Vishay) matches all critical electrical parameters and maintains the same impedance specification (80 Ohms). This part is suitable for direct substitution in applications where forward voltage specification is not explicitly required in the design.

Alternative Manufacturers with Acceptable Variations:

The onsemi MMSZ39T1G and SZMMSZ39T1G maintain the 39 V nominal voltage and 500 mW power rating but feature 130 Ohms impedance and lower reverse leakage (50 nA @ 27.3 V). These characteristics are acceptable for most circuit applications where impedance tolerance is within design margins. The SZMMSZ39T1G includes AEC-Q101 automotive qualification.

The Diodes Incorporated BZT52C39-13-F and BZT52C39-7-F are functionally equivalent with extended temperature range (-65°C to 150°C). The BZT52C39-7-F is available in Cut Tape format for automated assembly processes.

Limited Substitution (Power Derating Required):

The BZT52C39Q-7-F (Diodes Incorporated) features reduced maximum power rating (370 mW versus 500 mW) and slightly higher tolerance (±5.13%). This part is suitable only for applications where the circuit design accommodates the lower power specification. AEC-Q101 qualification is available for automotive applications.

Obsolete Parts (Not Recommended for New Designs):

The MMSZ5259B-HE3-08 (Vishay) is marked Obsolete and should not be selected for new designs, though it remains electrically compatible if existing inventory must be consumed.

Frequently Asked Questions (FAQ)

Q: Can I substitute MMSZ39T1G for MMSZ5259B-TP in my circuit?

A: Yes. The MMSZ39T1G maintains identical Zener voltage (39 V), power rating (500 mW), and forward voltage characteristics. The impedance difference (130 Ohms versus 80 Ohms) is acceptable in most applications. Verify that your circuit design does not impose strict impedance requirements before substitution.

Q: What is the difference between the onsemi MMSZ39T1G and SZMMSZ39T1G?

A: Both parts are electrically identical with 39 V Zener voltage and 500 mW power rating. The primary difference is packaging: MMSZ39T1G is supplied in Cut Tape & Digi-Reel format, while SZMMSZ39T1G is supplied in Tape & Reel format. The SZMMSZ39T1G includes AEC-Q101 automotive qualification. Select based on your manufacturing process requirements and whether automotive qualification is necessary.

Q: Why does BZT52C39Q-7-F have lower power rating (370 mW) than the original part (500 mW)?

A: The BZT52C39Q-7-F is a different product variant within the BZT52 series. While it maintains the 39 V Zener voltage specification, the reduced power rating reflects different thermal and electrical design characteristics. This part is suitable only for applications where the circuit design accommodates 370 mW maximum dissipation. Do not use as a direct substitute in designs requiring 500 mW capability.

Q: Is the extended temperature range of BZT52C39-7-F (-65°C to 150°C) better than the original MMSZ5259B-TP (-55°C to 150°C)?

A: The extended lower temperature limit (-65°C versus -55°C) provides additional operational margin for applications exposed to extreme cold environments. If your application operates only within -55°C to 150°C, both parts are functionally equivalent. If your application requires operation below -55°C, the BZT52C39-7-F is required.

Q: Can I use MMSZ5259B-7-F (Diodes Incorporated) instead of MMSZ5259B-TP (Micro Commercial Co)?

A: Yes. The MMSZ5259B-7-F is a direct electrical equivalent with identical Zener voltage (39 V), power rating (500 mW), impedance (80 Ohms), and reverse leakage characteristics (100 nA @ 30 V). The extended operating temperature range (-65°C to 150°C) provides additional margin. Both are ROHS3 compliant and Active status.

Q: What packaging formats are available for 39 V, 500 mW SOD-123 Zener diodes?

A: Available packaging formats include Tape & Reel (TR), Cut Tape (CT), and Digi-Reel. The MMSZ5259B-TP is supplied in Tape & Reel format. Alternative parts are available in Cut Tape & Digi-Reel (MMSZ39T1G, MMSZ5259B-HE3-08, MMSZ5259BT1G) or Tape & Reel (SZMMSZ39T1G, BZT52C39-13-F, BZT52C39-7-F, BZT52C39Q-7-F, DDZ9716-7, MMSZ5259B-7-F, MMSZ5259B-E3-08). Select based on your manufacturing assembly process.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed are ROHS3 compliant. All parts also have Moisture Sensitivity Level 1 (Unlimited) and REACH Unaffected status, matching the original MMSZ5259B-TP specifications.

Q: Which substitute part has the lowest reverse leakage current?

A: The onsemi MMSZ39T1G and SZMMSZ39T1G, along with the Diodes Incorporated DDZ9716-7, feature the lowest reverse leakage current at 50 nA (measured at different reference voltages: 27.3 V and 29.6 V respectively). The original MMSZ5259B-TP and most alternatives specify 100 nA @ 30 V. Lower leakage current may be beneficial in precision analog circuits or low-power applications.

Q: Can I use automotive-qualified parts (AEC-Q101) in non-automotive applications?

A: Yes. Automotive-qualified parts (SZMMSZ39T1G, MMSZ5259B-HE3-08, BZT52C39Q-7-F) meet or exceed the electrical and reliability requirements of non-automotive applications. Using automotive-qualified components in non-automotive designs provides additional quality assurance and reliability margin.

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